4.2 a beta-emitting radioactive isotope called iodine-131 is often released into the air during nuclear
accidents. it can settle on skin and clothing and can be inhaled or ingested. iodine is absorbed in
the body by the thyroid gland, where it is used to make molecules that travel throughout the body.
when the thyroid gland has enough iodine, any excess iodine is removed by the body. if a nuclear
accident occurs at a power plant, workers are asked to ingest potassium iodide tablets which
contain a stable isotope of iodine. explain how this minimises the risk of damage to their bodies.

On a hot saturday morning while people are working inside, the air conditioner keeps the temperature inside the building at 22degreesc. at noon the air conditioner is turned off, and the people go home. the temperature outside is a constant 33degreesc for the rest of the afternoon. if the time constant for the building is 4 hr, what will be the temperature inside the building at 4 : 00 font size decreased by 2 upper p . font size decreased by 2 upper m .? at 6 : 00 font size decreased by 2 upper p . font size decreased by 2 upper m .? when will the temperature inside the building reach 24degreesc? 324281